Nikolaos Georgakarakos- PhD
- Research Associate at New York University Abu Dhabi
Nikolaos Georgakarakos
- PhD
- Research Associate at New York University Abu Dhabi
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68
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Introduction
Nikolaos Georgakarakos currently works at the Department of Physics, New York University Abu Dhabi. Nikolaos does research in Applied Mathematics, Theoretical Physics, Celestial Mechanics and Dynamical Astronomy. His current research interests focus
on habitable planets.
Current institution
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Publications
Publications (68)
In this work we revisit the problem of the dynamical stability of hierarchical triple systems with applications to circumbinary planetary orbits. We derive critical semimajor axes based on simulating and analyzing the dynamical behavior of 3 × 10 ⁸ binary star–planet configurations. For the first time, three-dimensional and eccentric planetary orbi...
HD34445 is a system that consists of a star and six planets. In some previous work, we investigated the dynamical stability of the system by means of numerical simulations. Here, we explore the system further by carrying out additional numerical experiments. A total of 100000 simulations confirm previous findings of the stability status of the syst...
In some recent work, we provided a quantitative explanation for the number asymmetry of Jupiter Trojans by hypothesizing a free-floating planet (FFP) flyby into the Solar System. In support of that explanation, this paper examines the influence of the same FFP flyby on the Hilda asteroids, which orbit stably in the 3:2 mean motion resonance with Ju...
It has previously been suggested that ejection and vapourization of Hermean surface material by meteoroids from comet 2P/Encke causes a seasonal enhancement in Mercury’s Ca exosphere observed by the NASA MESSENGER spacecraft in 2011-2015. The ESA/JAXA BepiColombo mission, now en route to Mercury, will likely provide the next set of observational te...
Exploring planetary systems similar to our solar system can provide a means to explore a large range of possibly temperate climates on Earth-like worlds. Rather than run hundreds of simulations with different eccentricities at fixed obliquities, our variable-eccentricity approach provides a means to cover an incredibly large parameter space. Herein...
In this study, we focus on learning Hamiltonian systems, which involves predicting the coordinate (q) and momentum (p) variables generated by a symplectic mapping. Based on Chen & Tao (2021), the symplectic mapping is represented by a generating function. To extend the prediction time period, we develop a new learning scheme by splitting the time s...
Context. This paper extends our previous study of the early evolution of Jupiter and its two Trojan swarms by introducing the possible perturbations of a free-floating planet (FFP) invading the Solar System.
Aims. In the framework of the invasion of a FFP, we aim to provide some new scenarios to explain the number asymmetry of the L4 and L5 Jupiter...
This paper extends our previous study (Li et al. 2023) of the early evolution of Jupiter and its two Trojan swarms by introducing the possible perturbations of a free floating planet (FFP) invading the Solar System. In the framework of the invasion of a FFP, we aim to provide some new scenarios to explain the number asymmetry of the L4 and L5 Jupit...
Context. More than 10 000 Jupiter Trojans have been detected so far. They are moving around the L4 and L5 triangular Lagrangian points of the Sun-Jupiter system and their distributions can provide important clues about the early evolution of the Solar System.
Aims. The number asymmetry of the L4 and L5 Jupiter Trojans is a longstanding problem. We...
A very long term variability (VLPP), with period of 875 days, was observed in the long-term light curve of FS Aurigae in 2011. This periodicity was calculated on 6 cycles. We re-examine the periodicity with new observations over of the past 5 yrs. A total of 18 yrs of observations confirm the hypothesis of a third body perturbing in a secular way t...
Context. More than 10000 Jupiter Trojans have been detected so far. They are moving around the L4 and L5 triangular Lagrangian points of the Sun-Jupiter system and their distributions can provide important clues to the early evolution of the Solar System. Aims. The number asymmetry of the L4 and L5 Jupiter Trojans is a longstanding problem. We aim...
The dynamical excitation of asteroids due to mean motion resonant interactions with planets is enhanced when their parent star leaves the main sequence. However, numerical investigation of resonant outcomes within post-main-sequence simulations is computationally expensive, limiting the extent to which detailed resonant analyses have been performed...
The dynamical excitation of asteroids due to mean motion resonant interactions with planets is enhanced when their parent star leaves the main sequence. However, numerical investigation of resonant outcomes within post-main-sequence simulations is computationally expensive, limiting the extent to which detailed resonant analyses have been performed...
Some Cataclysmic Variables (CVs) exhibits a very long photometric period (VLPP). We calculate the properties of a hypothetical third body, initially assumed on circular--planar orbit, by matching the modelled VLPP to the observed one of four CVs studied here: {\sl LU Camelopardalis} (LU Cam), QZ Serpentis (QZ Ser), V1007 Herculis (V1007 Her) and BK...
Some cataclysmic variables (CVs) exhibit a very long photometric period (VLPP). We calculate the properties of a hypothetical third body, initially assumed to be on a circular–planar orbit, by matching the modelled VLPP to the observed one of four CVs studied here: LU Camelopardalis, QZ Serpentis, V1007 Herculis and BK Lyncis. The eccentric and low...
Most recently, machine learning has been used to study the dynamics of integrable Hamiltonian systems and the chaotic 3-body problem. In this work, we consider an intermediate case of regular motion in a non-integrable system: the behaviour of objects in the 2:3 mean motion resonance with Neptune. We show that, given initial data from a short 6250...
Most recently, machine learning has been used to study the dynamics of integrable Hamiltonian systems and the chaotic 3-body problem. In this work, we consider an intermediate case of regular motion in a non-integrable system: the behaviour of objects in the 2:3 mean motion resonance with Neptune. We show that, given initial data from a short 6250...
Two circumbinary planets have been recently discovered by TESS. The main aim of this work is to explore whether it is possible, besides the discovered circumbinary planet, to have an Earth-like planet within the habitable zone of the system. We carry out numerical simulations over the whole range of the two habitable zones in order to see whether a...
Two circumbinary planets have been recently discovered by TESS. The main aim of this work is to explore whether it is possible, besides the discovered circumbinary planet, to have an Earth-like planet within the habitable zone of the system. We carry out numerical simulations over the whole range of the two habitable zones in order to see whether a...
The last phase of the formation of rocky planets is dominated by collisions among Moon- to Mars-sized planetary embryos. Simulations of this phase need to handle the difficulty of including the post-impact material without saturating the numerical integrator. A common approach is to include the collision-generated material by clustering it into few...
The last phase of the formation of rocky planets is dominated by collisions among Moon- to Mars-sized planetary embryos. Simulations of this phase need to handle the difficulty of including the post-impact material without saturating the numerical integrator. A common approach is to include the collision-generated material by clustering it into few...
We investigate the long-term dynamical survival of Earth co-orbital asteroids, focusing on near-circular, near-planar orbits which existing studies suggest are the most stable. Through numerical integration of test particles we show that about a quarter of an initial population can survive for at least 50\% of the age of the solar system with horse...
We investigate the long-term dynamical survival of Earth co-orbital asteroids, focusing on near-circular, near-planar orbits which existing studies suggest are the most stable. Through numerical integration of test particles we show that about a quarter of an initial population can survive for at least 50 per cent of the age of the Solar system wit...
Our knowledge of white dwarf planetary systems predominately arises from the region within a few Solar radii of the white dwarfs, where minor planets breakup, form rings and discs, and accrete on to the star. The entry location, angle and speed into this Roche sphere has rarely been explored but crucially determines the initial geometry of the debr...
Our knowledge of white dwarf planetary systems predominately arises from the region within a few Solar radii of the white dwarfs, where minor planets break up, form rings and discs, and accrete onto the star. The entry location, angle and speed into this Roche sphere has rarely been explored but crucially determines the initial geometry of the debr...
Determining habitable zones in binary star systems can be a challenging task due to the combination of perturbed planetary orbits and varying stellar irradiation conditions. The concept of “dynamically informed habitable zones” allows us, nevertheless, to make predictions on where to look for habitable worlds in such complex environments. Dynamical...
Determining habitable zones in binary star systems can be a challenging task due to the combination of perturbed planetary orbits and varying stellar irradiation conditions. The concept of "dynamically informed habitable zones" allows us, nevertheless, to make predictions on where to look for habitable worlds in such complex environments. Dynamical...
Several concepts have been brought forward to determine where terrestrial planets are likely to remain habitable in multi-stellar environments. Isophote-based habitable zones, for instance, rely on insolation geometry to predict habitability, whereas radiative habitable zones take the orbital motion of a potentially habitable planet into account. D...
Several concepts have been brought forward to determine where terrestrial planets are likely to remain habitable in multi-stellar environments. Isophote-based habitable zones, for instance, rely on insolation geometry to predict habitability, whereas Radiative Habitable Zones take the orbital motion of a potentially habitable planet into account. D...
In 2010 the first planet was discovered around star HD 34445. Recently, another five planets were announced orbiting the same star. It is a rather dense multiplanet system with some of its planets having separations of fractions of an au and minimum masses ranging from Neptune to sub-Jupiter ones. Given the number of planets and the various uncerta...
We investigate the hypothesis that the size of the habitable zone around hardened binaries in dense star-forming regions increases. Our results indicate that this hypothesis is essentially incorrect. Although certain binary star configurations permit extended habitable zones, such set-ups typically require all orbits in a system to be near-circular...
In 2010 the first planet was discovered around star HD 34445. Recently, another five planets were announced orbiting the same star. It is a rather dense multi-planet system with some of its planets having separations of fractions of an au and minimum masses ranging from Neptune to sub-Jupiter ones. Given the number of planets and the various uncert...
We investigate the hypothesis that the size of the habitable zone around hardened binaries in dense star-forming regions increases. Our results indicate that this hypothesis is essentially incorrect. Although certain binary star configurations permit extended habitable zones, such setups typically require all orbits in a system to be near circular....
Previous full-lifetime simulations of single-star multi-planet systems across all phases of stellar evolution have predominately assumed coplanar or nearly coplanar orbits. Here we assess the consequences of this assumption by removing it and exploring the effect of giant branch mass loss on the stability of two-planet systems with small to moderat...
Previous full-lifetime simulations of single-star multi-planet systems across all phases of stellar evolution have predominately assumed coplanar or nearly-coplanar orbits. Here we assess the consequences of this assumption by removing it and exploring the effect of giant branch mass loss on the stability of two-planet systems with small to moderat...
The presence of giant planets influences potentially habitable worlds in numerous ways. Massive celestial neighbors can facilitate the formation of planetary cores and modify the influx of asteroids and comets towards Earth-analogs later on. Furthermore, giant planets can indirectly change the climate of terrestrial worlds by gravitationally alteri...
The presence of giant planets influences potentially habitable worlds in numerous ways. Massive celestial neighbors can facilitate the formation of planetary cores and modify the influx of asteroids and comets towards Earth-analogs later on. Furthermore, giant planets can indirectly change the climate of terrestrial worlds by gravitationally alteri...
The scenario and the efficiency of water transport by icy asteroids and comets are still amongst the most important unresolved questions about the early phases of planetary systems. The detection of Proxima Centauri b (PCb), which moves in the habitable zone, triggered a debate whether or not this planet can be habitable depending on its formation...
The scenario and efficiency of water transport by icy asteroids and comets are still amongst the most important unresolved questions of planetary systems. A better understanding of cometary dynamics in extrasolar systems shall provide information about cometary reservoirs and give an insight into water transport especially to planets in the habitab...
The Kepler era of exoplanetary discovery has presented the Astronomical community with a cornucopia of planetary systems very different from the one which we inhabit. It has long been known that Jupiter plays a major role in the orbital parameters of Mars and it's climate, but there is also a long-standing belief that Jupiter would play a similar r...
The Kepler era of exoplanetary discovery has presented the Astronomical community with a cornucopia of planetary systems very different from the one which we inhabit. It has long been known that Jupiter plays a major role in the orbital parameters of Mars and it's climate, but there is also a long-standing belief that Jupiter would play a similar r...
Nearly every star known to host planets will become a white dwarf, and nearly 100 planet-hosts are now known to be accompanied by binary stellar companions. Here, we determine how a binary companion triggers instability in otherwise unconditionally stable single-star two-planet systems during the giant branch and white dwarf phases of the planet ho...
Nearly every star known to host planets will become a white dwarf, and nearly 100 planet-hosts are now known to be accompanied by binary stellar companions. Here, we determine how a binary companion triggers instability in otherwise unconditionally stable single-star two-planet systems during the giant branch and white dwarf phases of the planet ho...
We study the long term orbital evolution of a terrestrial planet under the gravitational perturbations of a giant planet. In particular, we are interested in situations where the two planets are in the same plane and are relatively close. We examine both possible configurations: the giant planet orbit being either outside or inside the orbit of the...
We study the long term orbital evolution of a terrestrial planet under the gravitational perturbations of a giant planet.
In particular, we are interested in situations where the two planets are in the same plane and are relatively close. We examine
both possible configurations: the giant planet orbit being either outside or inside the orbit of the...
We know that planetary systems are just as common around white dwarfs as around main sequence stars. However, self-consistently
linking a planetary system across these two phases of stellar evolution through the violent giant branch poses computational
challenges, and previous studies restricted architectures to equal-mass planets. Here, we remove...
We know that planetary systems are just as common around white dwarfs as around main sequence stars. However, self-consistently linking a planetary system across these two phases of stellar evolution through the violent giant branch poses computational challenges, and previous studies restricted architectures to equal-mass planets. Here, we remove...
Perturbation theory in the three body problem has greatly advanced our ability to understand and model a variety of systems ranging from artificial satellites to stars and from extrasolar planets to asteroid-Jupiter interactions. In a series of papers, we developed an analytical technique for estimating the orbital eccentricity of the inner binary...
The herein presented analytical framework fully describes the motion of
coplanar systems consisting of a stellar binary and a planet orbiting both
stars on orbital as well as secular timescales. Perturbations of the Runge-Lenz
vector are used to derive short period evolution of the system, while octupole
secular theory is applied to describe its lo...
Determining planetary habitability is a complex matter, as the interplay
between a planet's physical and atmospheric properties with stellar insolation
has to be studied in a self consistent manner. Standardized atmospheric models
for Earth-like planets exist and are commonly accepted as a reference for
estimates of Habitable Zones. In order to def...
To date, 17 circumbinary planets have been discovered. In this paper, we focus our attention on the stability of the Kepler
circumbinary planetary systems with only one planet, i.e. Kepler-16, Kepler-34, Kepler-35, Kepler-38, Kepler-64 and Kepler-413.
In addition to their intrinsic interest, the study of such systems is an opportunity to test our u...
Currently, a number of circumbinary planets have been discovered. In
this paper, we focus our attention on the long term stability (1Gyr) of
the Kepler circumbinary planetary systems with only one planet, i.e.
Kepler-16, Kepler-34, Kepler-35, Kepler-38 and Kepler 64. The
investigation is done by means of numerical simulations. By using two
differen...
In this paper we study numerically the effect of the initial mutual orbital
inclination on the stability of hierarchical triple systems with initially
circular orbits. Our aim is to investigate the possibility that the stability
boundary may be independent of the orbital inclination for certain mass ratios.
We integrate numerically the equations of...
The triple asteroids and triple Kuiper belt objects (collectively called the
triple minor planets) in the Solar system are of particular interest to the
scientific community since the discovery of the first triple asteroid system in
2004. In this paper, the Hill stability of the nine known triple minor planets
in the Solar system is investigated. S...
Binary and multiple systems constitute more than half of the total stellar population in the solar neighbourhood. Their frequent
occurrence as well as the fact that more than 70 planets have already been discovered in such configurations – most notably
the telluric companion of α Cen B – make them interesting targets in the search for habitable wor...
With more and more extrasolar planets discovered in and around binary star
systems, questions concerning the determination of the classical Habitable Zone
arise. Do the radiative and gravitational perturbations of the second star
influence the extent of the Habitable Zone significantly, or is it sufficient
to consider the host-star only? In this ar...
2 128 V. Olgas str., Thessaloniki 54645, Greece Hénon [8] used an inclined billiard to investigate aspects of chaotic scattering which occur in satellite encounters and in other situations. His model consisted of a piecewise mapping which described the motion of a point particle bouncing elastically on two disks. A one parameter family of orbits, n...
In a series of papers, we developed a technique for estimating the inner eccentricity in hierarchical triple systems, with
the inner orbit being initially circular. However, for certain combinations of the masses and the orbital elements, the secular
part of the solution failed. In this paper, we derive a new solution for the secular part of the in...
In this paper, we give a summary of stability criteria that have been derived for hierarchical triple systems over the past
few decades. We give a brief description and we discuss the criteria that are based on the generalisation of the concept of
zero velocity surfaces of the restricted three body problem, to the general case. We also present crit...
In previous papers, we developed a technique for estimating the inner eccentricity in hierarchical triple systems, with the
inner orbit being initially circular. We considered systems with well-separated components and different initial setups (e.g.,
coplanar and non-coplanar orbits). However, the systems we examined had comparable masses. In the p...
We develop a technique for estimating the inner eccentricity in hierarchical triple systems, with the inner orbit being initially circular, while the outer one is eccentric. We consider coplanar systems with well-separated components and comparable masses. The derivation of short-period terms is based on an expansion of the rate of change of the Ru...
We develop a technique for estimating the inner eccentricity in hierarchical triple systems with well-separated components.
We investigate systems with initially circular and coplanar orbits and comparable masses. The technique is based on an expansion
of the rate of change of the Runge—Lenz vector for calculating short period terms by using first-...
In a previous paper, we developed a technique for estimating the inner eccentricity in coplanar hierarchical triple systems on initially circular orbits, with comparable masses and with well-separated components, based on an expansion of the rate of change of the Runge-Lenz vector. Now, the same technique is extended to non-coplanar orbits. However...
Thesis (Ph. D.)--University of Edinburgh, 2001.
